April 16, 2009 -- Most patients facing elective surgery still don't tell their surgeons or anesthesiologists about herbal supplements they are taking; many doctors still don't ask, and the failure to communicate can have a big impact on surgical risk.

Even though they might say "natural" or "herbal" on the bottle, commonly used herbal remedies such as ginkgo biloba, ginseng, garlic, or echinacea can be dangerous when used in the days before surgery, plastic surgeon David J Rowe, MD, writes in the latest issue of the Aesthetic Surgery Journal.

Yet studies suggest as many as 70% of patients don't tell their doctors they are taking herbal supplements, he tells WebMD.

"There are a lot of reasons for this," he says. "Patients may think their doctors don't know anything about herbal supplements or they might believe their doctors will consider the use of these products 'quack' therapy."

It is important that patients tell their doctors about all the medications they are taking, including herbal supplements, before surgery. And doctors should provide patients with a list of supplements to avoid, Rowe says.

In a survey of plastic surgery patients published in February 2006, 55% reported taking at least one herbal supplement on a daily basis.

The most popular herbal remedies were the joint supplements chondroitin and glucosamine; the banned stimulant ephedra; and the cold remedy echinacea.

Surgery Risks of Herbal Supplements

In his newly published analysis, Rowe lists the herbal supplements that he tells patients to stop taking two weeks before surgery.

Supplements that are known or suspected to increase bleeding risk include:

In addition, St. John's wort and dong quai increase photosensitivity, which can be especially problematic for patients having laser skin procedures, Rowe says.

In July 2001, herbal supplement researcher Chun-Su Yuan, MD, PhD, and colleagues examined the impact of herbal supplement use on surgical outcomes in a review published in The Journal of the American Medical Association.

In that review, Yuan and colleagues called on doctors to ask about current and past herbal use prior to surgery.

"Although there has been initiation of herbal medicine into medical school curricula at several institutions, many practicing physicians remain unaware of potential perioperative complications of herbal medication use," they write.

Yuan tells WebMD that there has not been a lot of progress since the review was published. Yuan is the director of the Tang Center for Herbal Medicine Research at the University of Chicago.

"Awareness has not increased that much," he says. "Some surgeons and anesthesiologists are asking, but many are not."

Since most patients who have elective surgery don't see their anesthesiologist until a few days before their procedure, Yuan says it may not be practical to expect them to know to stop taking herbal supplements two weeks ahead of time.

"Even stopping for a few days is better than not stopping at all," he says.